A year after failing to buy Yahoo for $44.6 billion, manic Microsoft chief finally has a deal with the second-fiddle search engine outfit. Companies agreed in July to band together to take on Google; Microsoft will pay for search technology, Yahoo will use Bing as its default engine. Investors, techies mixed on how agreement actually fights Google; "People haven't figured it out." Microsoft shares down 5.4% in past year. Detroit native dropped out of Stanford M.B.A. program to join Harvard classmate Bill Gates 1980 as employee number 30. Became chief exec 2000. Famous for impassioned stage antics: pretended to stomp on an iPhone at recent company event after an employee snapped a picture with Apple's offending device.